/*
 *    PostgreSQL type definitions for the INET and CIDR types.
 *
 *    src/backend/utils/adt/network.c
 *
 *    Jon Postel RIP 16 Oct 1998
 *
 * This source code file contains modifications made by THL A29 Limited ("Tencent Modifications").
 * All Tencent Modifications are Copyright (C) 2023 THL A29 Limited.
 *
 */

#include "postgres.h"

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "access/hash.h"
#include "catalog/pg_type.h"
#include "common/ip.h"
#include "libpq/libpq-be.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/inet.h"


static int32 network_cmp_internal(inet *a1, inet *a2);
static bool addressOK(unsigned char *a, int bits, int family);
static inet *internal_inetpl(inet *ip, int64 addend);


/*
 * Common INET/CIDR input routine
 */
static inet *
network_in(char *src, bool is_cidr)
{// #lizard forgives
    int            bits;
    inet       *dst;

    dst = (inet *) palloc0(sizeof(inet));

    /*
     * First, check to see if this is an IPv6 or IPv4 address.  IPv6 addresses
     * will have a : somewhere in them (several, in fact) so if there is one
     * present, assume it's V6, otherwise assume it's V4.
     */

    if (strchr(src, ':') != NULL)
        ip_family(dst) = PGSQL_AF_INET6;
    else
        ip_family(dst) = PGSQL_AF_INET;

    bits = inet_net_pton(ip_family(dst), src, ip_addr(dst),
                         is_cidr ? ip_addrsize(dst) : -1);
    if ((bits < 0) || (bits > ip_maxbits(dst)))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
        /* translator: first %s is inet or cidr */
                 errmsg("invalid input syntax for type %s: \"%s\"",
                        is_cidr ? "cidr" : "inet", src)));

    /*
     * Error check: CIDR values must not have any bits set beyond the masklen.
     */
    if (is_cidr)
    {
        if (!addressOK(ip_addr(dst), bits, ip_family(dst)))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                     errmsg("invalid cidr value: \"%s\"", src),
                     errdetail("Value has bits set to right of mask.")));
    }

    ip_bits(dst) = bits;
    SET_INET_VARSIZE(dst);

    return dst;
}

Datum
inet_in(PG_FUNCTION_ARGS)
{
    char       *src = PG_GETARG_CSTRING(0);

    PG_RETURN_INET_P(network_in(src, false));
}

Datum
cidr_in(PG_FUNCTION_ARGS)
{
    char       *src = PG_GETARG_CSTRING(0);

    PG_RETURN_INET_P(network_in(src, true));
}


/*
 * Common INET/CIDR output routine
 */
static char *
network_out(inet *src, bool is_cidr)
{
    char        tmp[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
    char       *dst;
    int            len;

    dst = inet_net_ntop(ip_family(src), ip_addr(src), ip_bits(src),
                        tmp, sizeof(tmp));
    if (dst == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                 errmsg("could not format inet value: %m")));

    /* For CIDR, add /n if not present */
    if (is_cidr && strchr(tmp, '/') == NULL)
    {
        len = strlen(tmp);
        snprintf(tmp + len, sizeof(tmp) - len, "/%u", ip_bits(src));
    }

    return pstrdup(tmp);
}

Datum
inet_out(PG_FUNCTION_ARGS)
{
    inet       *src = PG_GETARG_INET_PP(0);

    PG_RETURN_CSTRING(network_out(src, false));
}

Datum
cidr_out(PG_FUNCTION_ARGS)
{
    inet       *src = PG_GETARG_INET_PP(0);

    PG_RETURN_CSTRING(network_out(src, true));
}


/*
 *        network_recv        - converts external binary format to inet
 *
 * The external representation is (one byte apiece for)
 * family, bits, is_cidr, address length, address in network byte order.
 *
 * Presence of is_cidr is largely for historical reasons, though it might
 * allow some code-sharing on the client side.  We send it correctly on
 * output, but ignore the value on input.
 */
static inet *
network_recv(StringInfo buf, bool is_cidr)
{// #lizard forgives
    inet       *addr;
    char       *addrptr;
    int            bits;
    int            nb,
                i;

    /* make sure any unused bits in a CIDR value are zeroed */
    addr = (inet *) palloc0(sizeof(inet));

    ip_family(addr) = pq_getmsgbyte(buf);
    if (ip_family(addr) != PGSQL_AF_INET &&
        ip_family(addr) != PGSQL_AF_INET6)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
        /* translator: %s is inet or cidr */
                 errmsg("invalid address family in external \"%s\" value",
                        is_cidr ? "cidr" : "inet")));
    bits = pq_getmsgbyte(buf);
    if (bits < 0 || bits > ip_maxbits(addr))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
        /* translator: %s is inet or cidr */
                 errmsg("invalid bits in external \"%s\" value",
                        is_cidr ? "cidr" : "inet")));
    ip_bits(addr) = bits;
    i = pq_getmsgbyte(buf);        /* ignore is_cidr */
    nb = pq_getmsgbyte(buf);
    if (nb != ip_addrsize(addr))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
        /* translator: %s is inet or cidr */
                 errmsg("invalid length in external \"%s\" value",
                        is_cidr ? "cidr" : "inet")));

    addrptr = (char *) ip_addr(addr);
    for (i = 0; i < nb; i++)
        addrptr[i] = pq_getmsgbyte(buf);

    /*
     * Error check: CIDR values must not have any bits set beyond the masklen.
     */
    if (is_cidr)
    {
        if (!addressOK(ip_addr(addr), bits, ip_family(addr)))
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                     errmsg("invalid external \"cidr\" value"),
                     errdetail("Value has bits set to right of mask.")));
    }

    SET_INET_VARSIZE(addr);

    return addr;
}

Datum
inet_recv(PG_FUNCTION_ARGS)
{
    StringInfo    buf = (StringInfo) PG_GETARG_POINTER(0);

    PG_RETURN_INET_P(network_recv(buf, false));
}

Datum
cidr_recv(PG_FUNCTION_ARGS)
{
    StringInfo    buf = (StringInfo) PG_GETARG_POINTER(0);

    PG_RETURN_INET_P(network_recv(buf, true));
}


/*
 *        network_send        - converts inet to binary format
 */
static bytea *
network_send(inet *addr, bool is_cidr)
{
    StringInfoData buf;
    char       *addrptr;
    int            nb,
                i;

    pq_begintypsend(&buf);
    pq_sendbyte(&buf, ip_family(addr));
    pq_sendbyte(&buf, ip_bits(addr));
    pq_sendbyte(&buf, is_cidr);
    nb = ip_addrsize(addr);
    if (nb < 0)
        nb = 0;
    pq_sendbyte(&buf, nb);
    addrptr = (char *) ip_addr(addr);
    for (i = 0; i < nb; i++)
        pq_sendbyte(&buf, addrptr[i]);
    return pq_endtypsend(&buf);
}

Datum
inet_send(PG_FUNCTION_ARGS)
{
    inet       *addr = PG_GETARG_INET_PP(0);

    PG_RETURN_BYTEA_P(network_send(addr, false));
}

Datum
cidr_send(PG_FUNCTION_ARGS)
{
    inet       *addr = PG_GETARG_INET_PP(0);

    PG_RETURN_BYTEA_P(network_send(addr, true));
}


Datum
inet_to_cidr(PG_FUNCTION_ARGS)
{
    inet       *src = PG_GETARG_INET_PP(0);
    int            bits;

    bits = ip_bits(src);

    /* safety check */
    if ((bits < 0) || (bits > ip_maxbits(src)))
        elog(ERROR, "invalid inet bit length: %d", bits);

    PG_RETURN_INET_P(cidr_set_masklen_internal(src, bits));
}

Datum
inet_set_masklen(PG_FUNCTION_ARGS)
{
    inet       *src = PG_GETARG_INET_PP(0);
    int            bits = PG_GETARG_INT32(1);
    inet       *dst;

    if (bits == -1)
        bits = ip_maxbits(src);

    if ((bits < 0) || (bits > ip_maxbits(src)))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("invalid mask length: %d", bits)));

    /* clone the original data */
    dst = (inet *) palloc(VARSIZE_ANY(src));
    memcpy(dst, src, VARSIZE_ANY(src));

    ip_bits(dst) = bits;

    PG_RETURN_INET_P(dst);
}

Datum
cidr_set_masklen(PG_FUNCTION_ARGS)
{
    inet       *src = PG_GETARG_INET_PP(0);
    int            bits = PG_GETARG_INT32(1);

    if (bits == -1)
        bits = ip_maxbits(src);

    if ((bits < 0) || (bits > ip_maxbits(src)))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("invalid mask length: %d", bits)));

    PG_RETURN_INET_P(cidr_set_masklen_internal(src, bits));
}

/*
 * Copy src and set mask length to 'bits' (which must be valid for the family)
 */
inet *
cidr_set_masklen_internal(const inet *src, int bits)
{
    inet       *dst = (inet *) palloc0(sizeof(inet));

    ip_family(dst) = ip_family(src);
    ip_bits(dst) = bits;

    if (bits > 0)
    {
        Assert(bits <= ip_maxbits(dst));

        /* Clone appropriate bytes of the address, leaving the rest 0 */
        memcpy(ip_addr(dst), ip_addr(src), (bits + 7) / 8);

        /* Clear any unwanted bits in the last partial byte */
        if (bits % 8)
            ip_addr(dst)[bits / 8] &= ~(0xFF >> (bits % 8));
    }

    /* Set varlena header correctly */
    SET_INET_VARSIZE(dst);

    return dst;
}

/*
 *    Basic comparison function for sorting and inet/cidr comparisons.
 *
 * Comparison is first on the common bits of the network part, then on
 * the length of the network part, and then on the whole unmasked address.
 * The effect is that the network part is the major sort key, and for
 * equal network parts we sort on the host part.  Note this is only sane
 * for CIDR if address bits to the right of the mask are guaranteed zero;
 * otherwise logically-equal CIDRs might compare different.
 */

static int32
network_cmp_internal(inet *a1, inet *a2)
{
    if (ip_family(a1) == ip_family(a2))
    {
        int            order;

        order = bitncmp(ip_addr(a1), ip_addr(a2),
                        Min(ip_bits(a1), ip_bits(a2)));
        if (order != 0)
            return order;
        order = ((int) ip_bits(a1)) - ((int) ip_bits(a2));
        if (order != 0)
            return order;
        return bitncmp(ip_addr(a1), ip_addr(a2), ip_maxbits(a1));
    }

    return ip_family(a1) - ip_family(a2);
}

Datum
network_cmp(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_INT32(network_cmp_internal(a1, a2));
}

/*
 *    Boolean ordering tests.
 */
Datum
network_lt(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_BOOL(network_cmp_internal(a1, a2) < 0);
}

Datum
network_le(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_BOOL(network_cmp_internal(a1, a2) <= 0);
}

Datum
network_eq(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_BOOL(network_cmp_internal(a1, a2) == 0);
}

Datum
network_ge(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_BOOL(network_cmp_internal(a1, a2) >= 0);
}

Datum
network_gt(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_BOOL(network_cmp_internal(a1, a2) > 0);
}

Datum
network_ne(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_BOOL(network_cmp_internal(a1, a2) != 0);
}

/*
 * MIN/MAX support functions.
 */
Datum
network_smaller(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    if (network_cmp_internal(a1, a2) < 0)
        PG_RETURN_INET_P(a1);
    else
        PG_RETURN_INET_P(a2);
}

Datum
network_larger(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    if (network_cmp_internal(a1, a2) > 0)
        PG_RETURN_INET_P(a1);
    else
        PG_RETURN_INET_P(a2);
}

/*
 * Support function for hash indexes on inet/cidr.
 */
Datum
hashinet(PG_FUNCTION_ARGS)
{
    inet       *addr = PG_GETARG_INET_PP(0);
    int            addrsize = ip_addrsize(addr);

    /* XXX this assumes there are no pad bytes in the data structure */
    return hash_any((unsigned char *) VARDATA_ANY(addr), addrsize + 2);
}

Datum
hashinetextended(PG_FUNCTION_ARGS)
{
	inet	   *addr = PG_GETARG_INET_PP(0);
	int			addrsize = ip_addrsize(addr);

	return hash_any_extended((unsigned char *) VARDATA_ANY(addr), addrsize + 2,
							 PG_GETARG_INT64(1));
}

/*
 *    Boolean network-inclusion tests.
 */
Datum
network_sub(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    if (ip_family(a1) == ip_family(a2))
    {
        PG_RETURN_BOOL(ip_bits(a1) > ip_bits(a2) &&
                       bitncmp(ip_addr(a1), ip_addr(a2), ip_bits(a2)) == 0);
    }

    PG_RETURN_BOOL(false);
}

Datum
network_subeq(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    if (ip_family(a1) == ip_family(a2))
    {
        PG_RETURN_BOOL(ip_bits(a1) >= ip_bits(a2) &&
                       bitncmp(ip_addr(a1), ip_addr(a2), ip_bits(a2)) == 0);
    }

    PG_RETURN_BOOL(false);
}

Datum
network_sup(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    if (ip_family(a1) == ip_family(a2))
    {
        PG_RETURN_BOOL(ip_bits(a1) < ip_bits(a2) &&
                       bitncmp(ip_addr(a1), ip_addr(a2), ip_bits(a1)) == 0);
    }

    PG_RETURN_BOOL(false);
}

Datum
network_supeq(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    if (ip_family(a1) == ip_family(a2))
    {
        PG_RETURN_BOOL(ip_bits(a1) <= ip_bits(a2) &&
                       bitncmp(ip_addr(a1), ip_addr(a2), ip_bits(a1)) == 0);
    }

    PG_RETURN_BOOL(false);
}

Datum
network_overlap(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    if (ip_family(a1) == ip_family(a2))
    {
        PG_RETURN_BOOL(bitncmp(ip_addr(a1), ip_addr(a2),
                               Min(ip_bits(a1), ip_bits(a2))) == 0);
    }

    PG_RETURN_BOOL(false);
}

/*
 * Extract data from a network datatype.
 */
Datum
network_host(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    char       *ptr;
    char        tmp[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];

    /* force display of max bits, regardless of masklen... */
    if (inet_net_ntop(ip_family(ip), ip_addr(ip), ip_maxbits(ip),
                      tmp, sizeof(tmp)) == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                 errmsg("could not format inet value: %m")));

    /* Suppress /n if present (shouldn't happen now) */
    if ((ptr = strchr(tmp, '/')) != NULL)
        *ptr = '\0';

    PG_RETURN_TEXT_P(cstring_to_text(tmp));
}

/*
 * network_show implements the inet and cidr casts to text.  This is not
 * quite the same behavior as network_out, hence we can't drop it in favor
 * of CoerceViaIO.
 */
Datum
network_show(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    int            len;
    char        tmp[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];

    if (inet_net_ntop(ip_family(ip), ip_addr(ip), ip_maxbits(ip),
                      tmp, sizeof(tmp)) == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                 errmsg("could not format inet value: %m")));

    /* Add /n if not present (which it won't be) */
    if (strchr(tmp, '/') == NULL)
    {
        len = strlen(tmp);
        snprintf(tmp + len, sizeof(tmp) - len, "/%u", ip_bits(ip));
    }

    PG_RETURN_TEXT_P(cstring_to_text(tmp));
}

Datum
inet_abbrev(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    char       *dst;
    char        tmp[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];

    dst = inet_net_ntop(ip_family(ip), ip_addr(ip),
                        ip_bits(ip), tmp, sizeof(tmp));

    if (dst == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                 errmsg("could not format inet value: %m")));

    PG_RETURN_TEXT_P(cstring_to_text(tmp));
}

Datum
cidr_abbrev(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    char       *dst;
    char        tmp[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];

    dst = inet_cidr_ntop(ip_family(ip), ip_addr(ip),
                         ip_bits(ip), tmp, sizeof(tmp));

    if (dst == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                 errmsg("could not format cidr value: %m")));

    PG_RETURN_TEXT_P(cstring_to_text(tmp));
}

Datum
network_masklen(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);

    PG_RETURN_INT32(ip_bits(ip));
}

Datum
network_family(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);

    switch (ip_family(ip))
    {
        case PGSQL_AF_INET:
            PG_RETURN_INT32(4);
            break;
        case PGSQL_AF_INET6:
            PG_RETURN_INT32(6);
            break;
        default:
            PG_RETURN_INT32(0);
            break;
    }
}

Datum
network_broadcast(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *dst;
    int            byte;
    int            bits;
    int            maxbytes;
    unsigned char mask;
    unsigned char *a,
               *b;

    /* make sure any unused bits are zeroed */
    dst = (inet *) palloc0(sizeof(inet));

    maxbytes = ip_addrsize(ip);
    bits = ip_bits(ip);
    a = ip_addr(ip);
    b = ip_addr(dst);

    for (byte = 0; byte < maxbytes; byte++)
    {
        if (bits >= 8)
        {
            mask = 0x00;
            bits -= 8;
        }
        else if (bits == 0)
            mask = 0xff;
        else
        {
            mask = 0xff >> bits;
            bits = 0;
        }

        b[byte] = a[byte] | mask;
    }

    ip_family(dst) = ip_family(ip);
    ip_bits(dst) = ip_bits(ip);
    SET_INET_VARSIZE(dst);

    PG_RETURN_INET_P(dst);
}

Datum
network_network(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *dst;
    int            byte;
    int            bits;
    unsigned char mask;
    unsigned char *a,
               *b;

    /* make sure any unused bits are zeroed */
    dst = (inet *) palloc0(sizeof(inet));

    bits = ip_bits(ip);
    a = ip_addr(ip);
    b = ip_addr(dst);

    byte = 0;

    while (bits)
    {
        if (bits >= 8)
        {
            mask = 0xff;
            bits -= 8;
        }
        else
        {
            mask = 0xff << (8 - bits);
            bits = 0;
        }

        b[byte] = a[byte] & mask;
        byte++;
    }

    ip_family(dst) = ip_family(ip);
    ip_bits(dst) = ip_bits(ip);
    SET_INET_VARSIZE(dst);

    PG_RETURN_INET_P(dst);
}

Datum
network_netmask(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *dst;
    int            byte;
    int            bits;
    unsigned char mask;
    unsigned char *b;

    /* make sure any unused bits are zeroed */
    dst = (inet *) palloc0(sizeof(inet));

    bits = ip_bits(ip);
    b = ip_addr(dst);

    byte = 0;

    while (bits)
    {
        if (bits >= 8)
        {
            mask = 0xff;
            bits -= 8;
        }
        else
        {
            mask = 0xff << (8 - bits);
            bits = 0;
        }

        b[byte] = mask;
        byte++;
    }

    ip_family(dst) = ip_family(ip);
    ip_bits(dst) = ip_maxbits(ip);
    SET_INET_VARSIZE(dst);

    PG_RETURN_INET_P(dst);
}

Datum
network_hostmask(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *dst;
    int            byte;
    int            bits;
    int            maxbytes;
    unsigned char mask;
    unsigned char *b;

    /* make sure any unused bits are zeroed */
    dst = (inet *) palloc0(sizeof(inet));

    maxbytes = ip_addrsize(ip);
    bits = ip_maxbits(ip) - ip_bits(ip);
    b = ip_addr(dst);

    byte = maxbytes - 1;

    while (bits)
    {
        if (bits >= 8)
        {
            mask = 0xff;
            bits -= 8;
        }
        else
        {
            mask = 0xff >> (8 - bits);
            bits = 0;
        }

        b[byte] = mask;
        byte--;
    }

    ip_family(dst) = ip_family(ip);
    ip_bits(dst) = ip_maxbits(ip);
    SET_INET_VARSIZE(dst);

    PG_RETURN_INET_P(dst);
}

/*
 * Returns true if the addresses are from the same family, or false.  Used to
 * check that we can create a network which contains both of the networks.
 */
Datum
inet_same_family(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0);
    inet       *a2 = PG_GETARG_INET_PP(1);

    PG_RETURN_BOOL(ip_family(a1) == ip_family(a2));
}

/*
 * Returns the smallest CIDR which contains both of the inputs.
 */
Datum
inet_merge(PG_FUNCTION_ARGS)
{
    inet       *a1 = PG_GETARG_INET_PP(0),
               *a2 = PG_GETARG_INET_PP(1);
    int            commonbits;

    if (ip_family(a1) != ip_family(a2))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("cannot merge addresses from different families")));

    commonbits = bitncommon(ip_addr(a1), ip_addr(a2),
                            Min(ip_bits(a1), ip_bits(a2)));

    PG_RETURN_INET_P(cidr_set_masklen_internal(a1, commonbits));
}

/*
 * Convert a value of a network datatype to an approximate scalar value.
 * This is used for estimating selectivities of inequality operators
 * involving network types.
 */
double
convert_network_to_scalar(Datum value, Oid typid)
{
    switch (typid)
    {
        case INETOID:
        case CIDROID:
            {
                inet       *ip = DatumGetInetPP(value);
                int            len;
                double        res;
                int            i;

                /*
                 * Note that we don't use the full address for IPv6.
                 */
                if (ip_family(ip) == PGSQL_AF_INET)
                    len = 4;
                else
                    len = 5;

                res = ip_family(ip);
                for (i = 0; i < len; i++)
                {
                    res *= 256;
                    res += ip_addr(ip)[i];
                }
                return res;

                break;
            }
        case MACADDROID:
            {
                macaddr    *mac = DatumGetMacaddrP(value);
                double        res;

                res = (mac->a << 16) | (mac->b << 8) | (mac->c);
                res *= 256 * 256 * 256;
                res += (mac->d << 16) | (mac->e << 8) | (mac->f);
                return res;
            }
        case MACADDR8OID:
            {
                macaddr8   *mac = DatumGetMacaddr8P(value);
                double        res;

                res = (mac->a << 24) | (mac->b << 16) | (mac->c << 8) | (mac->d);
                res *= ((double) 256) * 256 * 256 * 256;
                res += (mac->e << 24) | (mac->f << 16) | (mac->g << 8) | (mac->h);
                return res;
            }
    }

    /*
     * Can't get here unless someone tries to use scalarltsel/scalargtsel on
     * an operator with one network and one non-network operand.
     */
    elog(ERROR, "unsupported type: %u", typid);
    return 0;
}

/*
 * int
 * bitncmp(l, r, n)
 *        compare bit masks l and r, for n bits.
 * return:
 *        <0, >0, or 0 in the libc tradition.
 * note:
 *        network byte order assumed.  this means 192.5.5.240/28 has
 *        0x11110000 in its fourth octet.
 * author:
 *        Paul Vixie (ISC), June 1996
 */
int
bitncmp(const unsigned char *l, const unsigned char *r, int n)
{
    unsigned int lb,
                rb;
    int            x,
                b;

    b = n / 8;
    x = memcmp(l, r, b);
    if (x || (n % 8) == 0)
        return x;

    lb = l[b];
    rb = r[b];
    for (b = n % 8; b > 0; b--)
    {
        if (IS_HIGHBIT_SET(lb) != IS_HIGHBIT_SET(rb))
        {
            if (IS_HIGHBIT_SET(lb))
                return 1;
            return -1;
        }
        lb <<= 1;
        rb <<= 1;
    }
    return 0;
}

/*
 * bitncommon: compare bit masks l and r, for up to n bits.
 *
 * Returns the number of leading bits that match (0 to n).
 */
int
bitncommon(const unsigned char *l, const unsigned char *r, int n)
{
    int            byte,
                nbits;

    /* number of bits to examine in last byte */
    nbits = n % 8;

    /* check whole bytes */
    for (byte = 0; byte < n / 8; byte++)
    {
        if (l[byte] != r[byte])
        {
            /* at least one bit in the last byte is not common */
            nbits = 7;
            break;
        }
    }

    /* check bits in last partial byte */
    if (nbits != 0)
    {
        /* calculate diff of first non-matching bytes */
        unsigned int diff = l[byte] ^ r[byte];

        /* compare the bits from the most to the least */
        while ((diff >> (8 - nbits)) != 0)
            nbits--;
    }

    return (8 * byte) + nbits;
}


/*
 * Verify a CIDR address is OK (doesn't have bits set past the masklen)
 */
static bool
addressOK(unsigned char *a, int bits, int family)
{
    int            byte;
    int            nbits;
    int            maxbits;
    int            maxbytes;
    unsigned char mask;

    if (family == PGSQL_AF_INET)
    {
        maxbits = 32;
        maxbytes = 4;
    }
    else
    {
        maxbits = 128;
        maxbytes = 16;
    }
    Assert(bits <= maxbits);

    if (bits == maxbits)
        return true;

    byte = bits / 8;

    nbits = bits % 8;
    mask = 0xff;
    if (bits != 0)
        mask >>= nbits;

    while (byte < maxbytes)
    {
        if ((a[byte] & mask) != 0)
            return false;
        mask = 0xff;
        byte++;
    }

    return true;
}


/*
 * These functions are used by planner to generate indexscan limits
 * for clauses a << b and a <<= b
 */

/* return the minimal value for an IP on a given network */
Datum
network_scan_first(Datum in)
{
    return DirectFunctionCall1(network_network, in);
}

/*
 * return "last" IP on a given network. It's the broadcast address,
 * however, masklen has to be set to its max bits, since
 * 192.168.0.255/24 is considered less than 192.168.0.255/32
 *
 * inet_set_masklen() hacked to max out the masklength to 128 for IPv6
 * and 32 for IPv4 when given '-1' as argument.
 */
Datum
network_scan_last(Datum in)
{
    return DirectFunctionCall2(inet_set_masklen,
                               DirectFunctionCall1(network_broadcast, in),
                               Int32GetDatum(-1));
}


/*
 * IP address that the client is connecting from (NULL if Unix socket)
 */
Datum
inet_client_addr(PG_FUNCTION_ARGS)
{
    Port       *port = MyProcPort;
    char        remote_host[NI_MAXHOST];
    int            ret;

    if (port == NULL)
        PG_RETURN_NULL();

    switch (port->raddr.addr.ss_family)
    {
        case AF_INET:
#ifdef HAVE_IPV6
        case AF_INET6:
#endif
            break;
        default:
            PG_RETURN_NULL();
    }

    remote_host[0] = '\0';

    ret = pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
                             remote_host, sizeof(remote_host),
                             NULL, 0,
                             NI_NUMERICHOST | NI_NUMERICSERV);
    if (ret != 0)
        PG_RETURN_NULL();

    clean_ipv6_addr(port->raddr.addr.ss_family, remote_host);

    PG_RETURN_INET_P(network_in(remote_host, false));
}


/*
 * port that the client is connecting from (NULL if Unix socket)
 */
Datum
inet_client_port(PG_FUNCTION_ARGS)
{
    Port       *port = MyProcPort;
    char        remote_port[NI_MAXSERV];
    int            ret;

    if (port == NULL)
        PG_RETURN_NULL();

    switch (port->raddr.addr.ss_family)
    {
        case AF_INET:
#ifdef HAVE_IPV6
        case AF_INET6:
#endif
            break;
        default:
            PG_RETURN_NULL();
    }

    remote_port[0] = '\0';

    ret = pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
                             NULL, 0,
                             remote_port, sizeof(remote_port),
                             NI_NUMERICHOST | NI_NUMERICSERV);
    if (ret != 0)
        PG_RETURN_NULL();

    PG_RETURN_DATUM(DirectFunctionCall1(int4in, CStringGetDatum(remote_port)));
}


/*
 * IP address that the server accepted the connection on (NULL if Unix socket)
 */
Datum
inet_server_addr(PG_FUNCTION_ARGS)
{
    Port       *port = MyProcPort;
    char        local_host[NI_MAXHOST];
    int            ret;

    if (port == NULL)
        PG_RETURN_NULL();

    switch (port->laddr.addr.ss_family)
    {
        case AF_INET:
#ifdef HAVE_IPV6
        case AF_INET6:
#endif
            break;
        default:
            PG_RETURN_NULL();
    }

    local_host[0] = '\0';

    ret = pg_getnameinfo_all(&port->laddr.addr, port->laddr.salen,
                             local_host, sizeof(local_host),
                             NULL, 0,
                             NI_NUMERICHOST | NI_NUMERICSERV);
    if (ret != 0)
        PG_RETURN_NULL();

    clean_ipv6_addr(port->laddr.addr.ss_family, local_host);

    PG_RETURN_INET_P(network_in(local_host, false));
}


/*
 * port that the server accepted the connection on (NULL if Unix socket)
 */
Datum
inet_server_port(PG_FUNCTION_ARGS)
{
    Port       *port = MyProcPort;
    char        local_port[NI_MAXSERV];
    int            ret;

    if (port == NULL)
        PG_RETURN_NULL();

    switch (port->laddr.addr.ss_family)
    {
        case AF_INET:
#ifdef HAVE_IPV6
        case AF_INET6:
#endif
            break;
        default:
            PG_RETURN_NULL();
    }

    local_port[0] = '\0';

    ret = pg_getnameinfo_all(&port->laddr.addr, port->laddr.salen,
                             NULL, 0,
                             local_port, sizeof(local_port),
                             NI_NUMERICHOST | NI_NUMERICSERV);
    if (ret != 0)
        PG_RETURN_NULL();

    PG_RETURN_DATUM(DirectFunctionCall1(int4in, CStringGetDatum(local_port)));
}


Datum
inetnot(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *dst;

    dst = (inet *) palloc0(sizeof(inet));

    {
        int            nb = ip_addrsize(ip);
        unsigned char *pip = ip_addr(ip);
        unsigned char *pdst = ip_addr(dst);

        while (nb-- > 0)
            pdst[nb] = ~pip[nb];
    }
    ip_bits(dst) = ip_bits(ip);

    ip_family(dst) = ip_family(ip);
    SET_INET_VARSIZE(dst);

    PG_RETURN_INET_P(dst);
}


Datum
inetand(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *ip2 = PG_GETARG_INET_PP(1);
    inet       *dst;

    dst = (inet *) palloc0(sizeof(inet));

    if (ip_family(ip) != ip_family(ip2))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("cannot AND inet values of different sizes")));
    else
    {
        int            nb = ip_addrsize(ip);
        unsigned char *pip = ip_addr(ip);
        unsigned char *pip2 = ip_addr(ip2);
        unsigned char *pdst = ip_addr(dst);

        while (nb-- > 0)
            pdst[nb] = pip[nb] & pip2[nb];
    }
    ip_bits(dst) = Max(ip_bits(ip), ip_bits(ip2));

    ip_family(dst) = ip_family(ip);
    SET_INET_VARSIZE(dst);

    PG_RETURN_INET_P(dst);
}


Datum
inetor(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *ip2 = PG_GETARG_INET_PP(1);
    inet       *dst;

    dst = (inet *) palloc0(sizeof(inet));

    if (ip_family(ip) != ip_family(ip2))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("cannot OR inet values of different sizes")));
    else
    {
        int            nb = ip_addrsize(ip);
        unsigned char *pip = ip_addr(ip);
        unsigned char *pip2 = ip_addr(ip2);
        unsigned char *pdst = ip_addr(dst);

        while (nb-- > 0)
            pdst[nb] = pip[nb] | pip2[nb];
    }
    ip_bits(dst) = Max(ip_bits(ip), ip_bits(ip2));

    ip_family(dst) = ip_family(ip);
    SET_INET_VARSIZE(dst);

    PG_RETURN_INET_P(dst);
}


static inet *
internal_inetpl(inet *ip, int64 addend)
{
    inet       *dst;

    dst = (inet *) palloc0(sizeof(inet));

    {
        int            nb = ip_addrsize(ip);
        unsigned char *pip = ip_addr(ip);
        unsigned char *pdst = ip_addr(dst);
        int            carry = 0;

        while (nb-- > 0)
        {
            carry = pip[nb] + (int) (addend & 0xFF) + carry;
            pdst[nb] = (unsigned char) (carry & 0xFF);
            carry >>= 8;

            /*
             * We have to be careful about right-shifting addend because
             * right-shift isn't portable for negative values, while simply
             * dividing by 256 doesn't work (the standard rounding is in the
             * wrong direction, besides which there may be machines out there
             * that round the wrong way).  So, explicitly clear the low-order
             * byte to remove any doubt about the correct result of the
             * division, and then divide rather than shift.
             */
            addend &= ~((int64) 0xFF);
            addend /= 0x100;
        }

        /*
         * At this point we should have addend and carry both zero if original
         * addend was >= 0, or addend -1 and carry 1 if original addend was <
         * 0.  Anything else means overflow.
         */
        if (!((addend == 0 && carry == 0) ||
              (addend == -1 && carry == 1)))
            ereport(ERROR,
                    (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                     errmsg("result is out of range")));
    }

    ip_bits(dst) = ip_bits(ip);
    ip_family(dst) = ip_family(ip);
    SET_INET_VARSIZE(dst);

    return dst;
}


Datum
inetpl(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    int64        addend = PG_GETARG_INT64(1);

    PG_RETURN_INET_P(internal_inetpl(ip, addend));
}


Datum
inetmi_int8(PG_FUNCTION_ARGS)
{
    inet       *ip = PG_GETARG_INET_PP(0);
    int64        addend = PG_GETARG_INT64(1);

    PG_RETURN_INET_P(internal_inetpl(ip, -addend));
}


Datum
inetmi(PG_FUNCTION_ARGS)
{// #lizard forgives
    inet       *ip = PG_GETARG_INET_PP(0);
    inet       *ip2 = PG_GETARG_INET_PP(1);
    int64        res = 0;

    if (ip_family(ip) != ip_family(ip2))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("cannot subtract inet values of different sizes")));
    else
    {
        /*
         * We form the difference using the traditional complement, increment,
         * and add rule, with the increment part being handled by starting the
         * carry off at 1.  If you don't think integer arithmetic is done in
         * two's complement, too bad.
         */
        int            nb = ip_addrsize(ip);
        int            byte = 0;
        unsigned char *pip = ip_addr(ip);
        unsigned char *pip2 = ip_addr(ip2);
        int            carry = 1;

        while (nb-- > 0)
        {
            int            lobyte;

            carry = pip[nb] + (~pip2[nb] & 0xFF) + carry;
            lobyte = carry & 0xFF;
            if (byte < sizeof(int64))
            {
                res |= ((int64) lobyte) << (byte * 8);
            }
            else
            {
                /*
                 * Input wider than int64: check for overflow.  All bytes to
                 * the left of what will fit should be 0 or 0xFF, depending on
                 * sign of the now-complete result.
                 */
                if ((res < 0) ? (lobyte != 0xFF) : (lobyte != 0))
                    ereport(ERROR,
                            (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                             errmsg("result is out of range")));
            }
            carry >>= 8;
            byte++;
        }

        /*
         * If input is narrower than int64, overflow is not possible, but we
         * have to do proper sign extension.
         */
        if (carry == 0 && byte < sizeof(int64))
            res |= ((int64) -1) << (byte * 8);
    }

    PG_RETURN_INT64(res);
}


/*
 * clean_ipv6_addr --- remove any '%zone' part from an IPv6 address string
 *
 * XXX This should go away someday!
 *
 * This is a kluge needed because we don't yet support zones in stored inet
 * values.  Since the result of getnameinfo() might include a zone spec,
 * call this to remove it anywhere we want to feed getnameinfo's output to
 * network_in.  Beats failing entirely.
 *
 * An alternative approach would be to let network_in ignore %-parts for
 * itself, but that would mean we'd silently drop zone specs in user input,
 * which seems not such a good idea.
 */
void
clean_ipv6_addr(int addr_family, char *addr)
{
#ifdef HAVE_IPV6
    if (addr_family == AF_INET6)
    {
        char       *pct = strchr(addr, '%');

        if (pct)
            *pct = '\0';
    }
#endif
}
